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Mirrors > Home > MPE Home > Th. List > fac3 | Structured version Visualization version GIF version |
Description: The factorial of 3. (Contributed by NM, 17-Mar-2005.) |
Ref | Expression |
---|---|
fac3 | ⊢ (!‘3) = 6 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-3 12020 | . . 3 ⊢ 3 = (2 + 1) | |
2 | 1 | fveq2i 6771 | . 2 ⊢ (!‘3) = (!‘(2 + 1)) |
3 | 2nn0 12233 | . . 3 ⊢ 2 ∈ ℕ0 | |
4 | facp1 13973 | . . 3 ⊢ (2 ∈ ℕ0 → (!‘(2 + 1)) = ((!‘2) · (2 + 1))) | |
5 | 3, 4 | ax-mp 5 | . 2 ⊢ (!‘(2 + 1)) = ((!‘2) · (2 + 1)) |
6 | fac2 13974 | . . . 4 ⊢ (!‘2) = 2 | |
7 | 2p1e3 12098 | . . . 4 ⊢ (2 + 1) = 3 | |
8 | 6, 7 | oveq12i 7280 | . . 3 ⊢ ((!‘2) · (2 + 1)) = (2 · 3) |
9 | 2cn 12031 | . . . 4 ⊢ 2 ∈ ℂ | |
10 | 3cn 12037 | . . . 4 ⊢ 3 ∈ ℂ | |
11 | 9, 10 | mulcomi 10967 | . . 3 ⊢ (2 · 3) = (3 · 2) |
12 | 3t2e6 12122 | . . 3 ⊢ (3 · 2) = 6 | |
13 | 8, 11, 12 | 3eqtri 2771 | . 2 ⊢ ((!‘2) · (2 + 1)) = 6 |
14 | 2, 5, 13 | 3eqtri 2771 | 1 ⊢ (!‘3) = 6 |
Colors of variables: wff setvar class |
Syntax hints: = wceq 1541 ∈ wcel 2109 ‘cfv 6430 (class class class)co 7268 1c1 10856 + caddc 10858 · cmul 10860 2c2 12011 3c3 12012 6c6 12015 ℕ0cn0 12216 !cfa 13968 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1801 ax-4 1815 ax-5 1916 ax-6 1974 ax-7 2014 ax-8 2111 ax-9 2119 ax-10 2140 ax-11 2157 ax-12 2174 ax-ext 2710 ax-sep 5226 ax-nul 5233 ax-pow 5291 ax-pr 5355 ax-un 7579 ax-cnex 10911 ax-resscn 10912 ax-1cn 10913 ax-icn 10914 ax-addcl 10915 ax-addrcl 10916 ax-mulcl 10917 ax-mulrcl 10918 ax-mulcom 10919 ax-addass 10920 ax-mulass 10921 ax-distr 10922 ax-i2m1 10923 ax-1ne0 10924 ax-1rid 10925 ax-rnegex 10926 ax-rrecex 10927 ax-cnre 10928 ax-pre-lttri 10929 ax-pre-lttrn 10930 ax-pre-ltadd 10931 ax-pre-mulgt0 10932 |
This theorem depends on definitions: df-bi 206 df-an 396 df-or 844 df-3or 1086 df-3an 1087 df-tru 1544 df-fal 1554 df-ex 1786 df-nf 1790 df-sb 2071 df-mo 2541 df-eu 2570 df-clab 2717 df-cleq 2731 df-clel 2817 df-nfc 2890 df-ne 2945 df-nel 3051 df-ral 3070 df-rex 3071 df-reu 3072 df-rab 3074 df-v 3432 df-sbc 3720 df-csb 3837 df-dif 3894 df-un 3896 df-in 3898 df-ss 3908 df-pss 3910 df-nul 4262 df-if 4465 df-pw 4540 df-sn 4567 df-pr 4569 df-tp 4571 df-op 4573 df-uni 4845 df-iun 4931 df-br 5079 df-opab 5141 df-mpt 5162 df-tr 5196 df-id 5488 df-eprel 5494 df-po 5502 df-so 5503 df-fr 5543 df-we 5545 df-xp 5594 df-rel 5595 df-cnv 5596 df-co 5597 df-dm 5598 df-rn 5599 df-res 5600 df-ima 5601 df-pred 6199 df-ord 6266 df-on 6267 df-lim 6268 df-suc 6269 df-iota 6388 df-fun 6432 df-fn 6433 df-f 6434 df-f1 6435 df-fo 6436 df-f1o 6437 df-fv 6438 df-riota 7225 df-ov 7271 df-oprab 7272 df-mpo 7273 df-om 7701 df-2nd 7818 df-frecs 8081 df-wrecs 8112 df-recs 8186 df-rdg 8225 df-er 8472 df-en 8708 df-dom 8709 df-sdom 8710 df-pnf 10995 df-mnf 10996 df-xr 10997 df-ltxr 10998 df-le 10999 df-sub 11190 df-neg 11191 df-nn 11957 df-2 12019 df-3 12020 df-4 12021 df-5 12022 df-6 12023 df-n0 12217 df-z 12303 df-uz 12565 df-seq 13703 df-fac 13969 |
This theorem is referenced by: fac4 13976 4bc2eq6 14024 ef4p 15803 ef01bndlem 15874 |
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